Biohaven’s previously rejected rare disease drug to get fresh FDA review

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A rare disease drug previously rejected by the Food and Drug Administration will get a second look, giving its developer, Biohaven, another shot at a regulatory clearance. 

The Connecticut-based drug developer revealed in a regulatory filing Thursday that its refreshed application for Vyglxia, a drug that treats a nerve-damaging disorder, has been accepted for a review by the agency. The FDA will convene a panel of experts to discuss the findings, and expects to issue a new verdict in the first quarter of next year, according to Biohaven.  

The announcement offers the chance for an important regulatory reversal for Biohaven, the second iteration of a migraine drug developer Pfizer acquired in 2022. This Biohaven “2.0” is led by the same management team as the original, but has been pursuing a pipeline of medicines for multiple different diseases.

The most advanced of those therapies is Vyglxia. Biohaven has been developing it for a group of rare genetic disorders collectively called spinocerebellar ataxia, through which progressive neuronal damage leads to problems with balance, coordination and speech. If approved, it could be the first marketed medicine for the condition. Some analysts have predicted north of $1 billion in annual sales. 

Yet Vyglxia has encountered roadblocks with multiple drug regulators. In Europe, the company withdrew an approval application after evaluators there questioned Biohaven’s supportive evidence. U.S. regulators were similarly skeptical. Despite findings suggesting Vyglxia might slow disease progression by as much as 70%, the FDA found the key experiment the company ran unconvincing in part because of its design. The regulator formally rejected the treatment last November.

Biohaven claimed to have been blindsided by the decision, which was one of many controversial rare disease drug rejections issued by former FDA leadership. It also turned to cost cuts afterwards.

Still, the company didn’t abandon Vyglxia, and resubmitted the application with "new positive supportive analyses,” according to Thursday’s regulatory filing.  

The new disclosure sent Biohaven shares up by about 25% and triggered a series of optimistic notes from Wall Street analysts. The scheduling of an advisory committee meeting “substantially increases the probability of approval,” wrote TD Cowen analyst Tyler Van Buren.  

Turnover at the agency’s highest ranks has also made analysts more bullish on Biohaven’s chances. The FDA has recently reversed multiple decisions issued by former leaders. It’s also expressed a desire to become more flexible in reviewing rare disease medicines, specifically.  

That shift in stance “opens a real possibility” that Vyglxia could get to market, added RBC Capital Markets analyst Leonid Timashev. He did caution, however, that Biohaven’s chances could depend “largely on how extensive those flexibility changes have been.”